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4 results on '"Cdma 2000"'

1. SVD based reconfigurable SRC filter for multi‐standard radio receivers.

Author

Agarwal, Ashok and Bopanna, Lakshmi

Abstract

With the recent growth in wireless industry, and changes that occur at a faster pace in radio standards, software defined radio (SDR) provides a flexible solution when compared with hardware radios. Channelisation and sample rate conversion (SRC) are two computational intensive tasks to be carried out in SDR receivers. Reconfigurable anti‐aliasing filter and channeliser with minimum reconfiguration overhead is needed for the design of SDR receivers. Low complexity, coefficientless cascaded‐integrator‐comb filters provides flexible reconfiguration for SRC over a wide integer range, but offers gain droop in the passband of interest. Moreover, they are not suitable for achieving SRC by fractional rates. In this study, the authors propose the design of variable digital filter (VDF) for gain droop compensation and fractional SRC to meet the spectral characteristics of multiple radio communication standards, employing singular value decomposition algorithm. The proposed design of VDF is tested for its reconfigurability with four radio standards, namely, GSM900, WCDMA/CDMA 2000 and WiMAX 802.16. Simulations carried out in MATLAB showed that the proposed VDF had improved spectral response in comparison to other methods proposed in literature. [ABSTRACT FROM AUTHOR]

Published
2016
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3. Dynamical Effects of Time Delays and Time Delay Compensation in Power Controlled DS-CDMA

Author

Gunnarsson, Fredrik, Gustafsson, Fredrik, and Blom, Jonas

Subjects
Automatic control, Oscillations, WCDMA, Reglerteknik, Describing functions, Time-delay compensation, Cdma 2000, Delay analysis, DS-CDMA, Dynamics, IS-95, Power control
Abstract

Transmission power control is essential in systems of the third-generation (3G) in order to optimize the bandwidth utilization, which is critical when variable data rates are used. One remaining problem is oscillations in the output powers, due to round-trip delays in the power control loops together with the power up-down command device. The oscillations are naturally quantified using discrete time-describing functions, which are introduced and applied. More importantly, time-delay compensation (TDC) is proposed to mitigate the oscillations. When employing TDC, the power control algorithm exhibits greater stability, which is important from a network perspective. Simulations illustrate the oscillations and the benefits of TDC. Moreover, the fading tracking capability is improved, and thus, less fading margin is needed. The results apply not only to wideband code division multiple access (WCDMA), but to other direct-sequence (DS) CDMA systems power controlled in a similar manner as well.

Published
2001

4. The Mobile Aircraft Maintenance Office Concept from a Wide Area Perspective

Author

NAVAL POSTGRADUATE SCHOOL MONTEREY CA, Perrella, Sil A., NAVAL POSTGRADUATE SCHOOL MONTEREY CA, and Perrella, Sil A.

Abstract

As mobile computing becomes more ubiquitous, through the use of very capable mobile computing devices and broadband wide-area wireless data networks, naval aviation maintenance has an opportunity to extend the reach of the Naval Aviation Logistics Command Management Information System (NALCOMIS) to fielded aircrew, maintenance technicians, and maintenance supervisors supporting out-of-local-area operations. The combination of the new mobile technologies and the wireless Internet makes modern Mobile Business (m-business) initiatives possible, but ushers in a host of new problems and issues that are radically different from those experienced with traditional fixed electronic business (e-business) projects. This thesis examines the concept and components that comprise m-business, details wide-area data over cellular technologies, and identifies problems and issues unique to m-business initiatives. Scenario-based "Use Cases" will be employed within the Unified Process (UP) framework to develop the three major artifacts of the UP's inception phase: the project's vision, a Use Case model, and a supplemental specification containing functional and nonfunctional requirements for an aircrew mobile aircraft maintenance application. The results of this study can serve as the foundation for the development of a complete mobile aircraft maintenance office. A detailed survey of the evolution of cellular technologies; a review of the Third Generation Wireless (3G) specification; the issues surrounding 3G's implementation; and an in-depth technical discussion of the two most predominant 3G system architectures, data capabilities, and required protocols is presented in the three appendices and are referenced throughout the thesis. (10 tables, 9 figures, 22 refs.), The original document contains color images.

Published
2003

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